[CCCure CISSP] Qs7 Physical Security: cccure QuizEngn doubts

classic Classic list List threaded Threaded
1 message Options
Reply | Threaded
Open this post in threaded view

[CCCure CISSP] Qs7 Physical Security: cccure QuizEngn doubts

Amlan Deb
Hello everyone,
I have some doubts regarding some cccure Quiz questions and concepts mentioned below. Would really appreciate it if you could take out some time and help me with them. Request you to please provide a quick reply as I need to appear for the exam in the month of July.



1.     Question: 233 | Difficulty: 2/5 | Relevancy: 3/3

Which of the following is the preferred way to suppress an electrical fire in an information center?

o     CO2

o      CO2, soda acid, or Halon

o      water or soda acid

o      ABC Rated Dry Chemical

You did not provide any answer to this question. Please review details below.

It must be noted that Halon is now banned in most country or cities.

The correct answer is: CO2:

The reason CO2 is preferred in an information center is the agent is considered a clean agent, as well as non-conductive. The agent evaporates and does not leave a residue on the equipment. CO2 can be hazardous to people so special care must be taken when implemented.

Water or Soda/Acid & Halon are incorrect choices: (old water extinguishers) will damage sensitive equipment as well as conduct electricity which could endanger the life of the person using such a fire extinghisher. Halon has been banned due to the Montreal Protocol.

ABC rated Dry chemical extinguishers in not a suitable choice: They are suitable for electrically energized fires, but they are not acceptable on sensitive equipment. It is like throwing a couple kilograms of flour in around in a room. It is extremely hard to clean off of equipment and some of the chemicals are corrosive in nature.





Another Source can be:
KRUTZ, Ronald L. & VINES, Russel D.
The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, page 335.

Special thanks to Glen Chandler for providing improvement to the question as well as references and new distracters.
Last updated on June 25th, 2007
Thanks to Mark Heckman for providing input to improve this question



For the purpose of the exam do not go outside of the 4 choices presented. YES, it is true that there are many other choices that would be adequate for a Data Centre. An agent such as IG-55 from Ardent would probably be a better choice than CO2, however it is NOT in the list of choices.  

You will also notice that Shon Harris and Krutz and Vines disagree on which one is the best.  This is why you must do your own research to supplement the books, sometimes books could be opiniated as well.

See some information about IG-55 below:

The Agent

o IG55 is a mixture of two naturally occurring atmospheric gases, Nitrogen and Argon.

o IG55 is stored compressed and uncondensed and is totally dry. When deployed, there is no condensation that can cause harm to moist sensitive equipment.

o IG 55 does not form harmful by products when used in a fire and the gas is totally non corrosive. The gas is stored and used at room temperature, thus avoiding any risk of damage due to exposure to low temperatures.

o IG55 does not affect the ozone layer and has a very short atmospheric lifetime. IG55 has no global warming potential.

o IG55 is colour- and odour-less. IG 55 is non conductive.

o IG55 has approximately the same density as air.

o The Oxygen Depletion Method

o IG55 is a mixture of Nitrogen and Argon that extinguishes fire by oxygen depletion.

Because the reduced oxygen atmosphere required to put out the fire still is breathable to humans, IG55 is ideal to use in normally occupied areas.

IG55 is clean and pure and leaves no residues that have to be taken care of after discharge. The gas is non corrosive and non conductive and can be used directly on electrical installations.

IG55 is used in closed areas –total flood. IG55 extinguishes the fire by depleting the oxygen level down to where no combustion can occur. Normal air contains 20.9% of oxygen. In order to put out a fire that level must be reduced down to 14% or less. At a concentration of 50% IG55 in a room, a typical oxygen level of 12.5% is achieved.

IG55 is suitable for fires in a gases and liquids, class B-fires. IG55 in a room, a typical oxygen level of 12.5% is achieved.

IG55 is suitable for fires in gases and liquids, class B-fires. IG55 is also suitable for putting out class A surface fires in wood, cloth and paper.

IG55 is not suitable for fires in substances that generates oxygen, like some reactive metals.

Personal Safety

In order to put out a fire the oxygen level must be reduced down to 14% or less. A normal system is dimensioned to reduce the oxygen level down to 12-13.8% depending on the type of hazard. This is a level that is considered safe for normally occupied areas, and the system may be used without restrictions like time delays and pre alarms.


Contributor: Eric Yandell



My doubt:  Why isn’t option ‘B’ the correct answer? If it’s because Halon is no longer accepted as a valid fire extinguisher gas agent, there are so many other Qs and concepts where Halon as a choice is considered correct answer. Like the question shown below:


1.     Question: 235 | Difficulty: 2/5 | Relevancy: 3/3

Which of the following suppresses combustion by disrupting a chemical reaction,  by doing so it kills the fire?

o     Halon

o      CO2

o      water

o      soda acid


The correct answer is:  Halon


You can find the list archive at:

CISSPstudy mailing list
[hidden email]

To UNSUBSCRIBE, SUBSCRIBE, or MANAGE your accout visit the link below: